Condensation Control Frequently Asked Questions

Condensation Control Frequently Asked Questions

We have gathered together a list of the most frequently asked questions that we get relating to the control of condensation in properties - if you have a question that isn’t answered here please feel free to “Ask our Expert” and we will be more than happy to help you.

What is condensation?

Condensation occurs when warm moisture laden air meets a cold surface. Ordinarily the air  in our atmosphere contains anything between 0 to 4% water vapour. The key factors involved in causing condensation are – The amount of water vapour in the property (measured in relative humidity), the amount of air circulation in the property and the air temperature both inside and outside. Basically the warmer the air temperature the greater its capacity for holding water vapour, therefore making it more likely that condensation will occur. As the air cools it will reach a point where it can no longer hold water vapour (The dew point) and the water vapour will start to condensate, forming as small droplets of water on the cooler surface – for example on windows.

When does condensation in buildings occur?

Condensation is usually a problem during the cooler winter months. People tend to close windows and “seal” up buildings meaning that the moisture laden air has nowhere to escape to.

What does condensation indicate?

When condensation is visible on windows it is a sure sign that there is too much water vapor within the air in the property or that the air circulation is not sufficient to allow the moisture laden air to escape.

Where does the water vapour in the air that causes condensation come from?

The air in a property gains moisture through evaporation from a number of sources. Obvious sources of moisture include water from baths, sinks and showering, and steam from cooking. Lees obvious culprits include plants, animals, and just general living by people. Newly built properties will acquire excess water vapour from the new materials and finishes used in the property. As the water evaporates from these products there will be high levels of relative humidity until the materials stabilise and the humid, moisture laden air is vented.

Does air circulation affect condensation within properties?

Air circulation affects the the supply of fresh air into the property. Poor air circulation causes the air next to windows to cool down faster. When air remains next to a cool surface it cools down faster than well circulated air. As the temperature within the room decreases so does its ability to hold water vapour and as a result there is more chance of condensation forming. Whenever possible try and open windows in the property to improve the flow of air. Further advice can be found in our Condensation Control Advice leaflet.

What is the difference between Rising damp and condensation?

Condensation can arise anywhere within the property as long as the right atmospheric conditions are available. Rising damp however is specific tot he ground floor only of the property. It appears mainly on outside walls (although it can also affect interior walls). Rising damp can rise to approx 1m above the floor level. Condensation is often misdiagnosed by inexperienced surveyors as Rising damp in ground floor conditions. This is where a skilled and trained surveyor is required for an accurate diagnosis.

How does the temperature affect condensation?

The amount of water vapour the air can hold is directly affected by the air temperature. Warmer air holds more moisture than colder air. When warm air cools it will begin to condensate.

Should I ignore condensation?

Condensation can cause damage not only to your home but your belongings too. Stains, mould and mildew are visual signs of a condensation problem but condensation can also lead to poor health and respiratory problems – for example asthma. Ignore condensation at your peril!

How can I cure condensation?

There is no simple cure for condensation as there are so many different factors involved. Our Condensation Control Advice leaflet gives various do’s and don’ts that should be followed as part of a healthy occupancy lifestyle. Air circulation, ventilation and heating are other key issues. In areas where there is high humidity present (for example kitchens and bathrooms) extractor fans will help control the flow of the moist air. One of the most effective ways to help control condensation is to have a positive pressure ventilation system installed. A positive pressure system will circulate dry, relatively warm air around the property to eliminate potential cold spots where condensation could form.